564 



CLASS II. ONYCHOPHORA. 



Generative Organs. The male organs (Fig. 343) consist of 

 a pair of testes (te), a pair of vesicles (v), vasa deferentia (v.d), 

 and accessory glandular tubules (/). All the above parts lie in 

 the central compartment of the body cavity. In P. capensis 

 the crural glands of the last (17th) pair of legs are enlarged and 

 prolonged into an elongated tube (a.g) placed in the lateral com- 

 partment of the body cavity. The right vas deferens passes, 

 in P. capensis, under both nerve-cords to join the left, and 

 form the enlarged tube (p), which, passing beneath the nerve- 

 cord of its side, runs to the external orifice. The enlarged 



FIG. 343. Male generative organs of Peripalus ca /tennis, viewed from the dorsal surface 

 (after Balfour). a.g Enlarged crural glands of last pair of legs ; F.16, 17, last pairs of 

 legs ; / small accessory glandular tubes ; p common duct into which the vasa deferentia 

 open ; te testis ; r seminal vesicle ; v.c. nerve-cord : v.d vas deferens. 



terminal portion possesses thick muscular walls, which serve 

 for the extrusion of the spermatophores. In some specimens 

 a different arrangement obtains, in that the left vas deferens 

 passes under both nerve-cords to join the right. The length of 

 the unpaired part of the vas deferens varies considerably in 

 length in the different groups of species. In the Cape species 

 it is of no great length, and the accessory glands open into its 

 terminal portion. In other species these glands open directly 

 to the exterior and independently of the vas deferens. The 

 spermatozoa * are long and thread-like. The head tapers at 

 * T. H. Montgomery, Zool. Jahrb. 14, 1900, p. 277. 



